diff --git a/15-introspective/tf-15.py b/15-introspective/tf-15.py
index 3ec896e..01f9553 100755
--- a/15-introspective/tf-15.py
+++ b/15-introspective/tf-15.py
@@ -1,32 +1,33 @@
 #!/usr/bin/env python
-
 import sys, re, operator, string, inspect
 
 #
 # The functions
 #
+def read_stop_words():
+    # Meta-level data: inspect.stack() and locals()
+    print "My name is " + inspect.stack()[0][3] + ", my arguments are " + str(locals().keys())
+    print "   and I'm being called from ", inspect.stack()[1][3]
+    with open('../stop_words.txt') as f:
+        stop_words = f.read().split(',')
+    stop_words.extend(list(string.ascii_lowercase))
+    return stop_words
+
 def extract_words(path_to_file):
-    """
-    Takes a path to a file and returns the non-stop
-    words, after properly removing nonalphanumeric chars
-    and normalizing for lower case
-    """
-    print "My name is " + inspect.stack()[0][3] + " and my arguments are " + str(locals().keys())
+    # Meta-level data: inspect.stack() and locals()
+    print "My name is " + inspect.stack()[0][3] + ", my arguments are " + str(locals().keys())
+    print "   and I'm being called from ", inspect.stack()[1][3]
     with open(locals()['path_to_file']) as f:
         str_data = f.read()
     pattern = re.compile('[\W_]+')
     word_list = pattern.sub(' ', str_data).lower().split()
-    with open('../stop_words.txt') as f:
-        stop_words = f.read().split(',')
-    stop_words.extend(list(string.ascii_lowercase))
+    stop_words = read_stop_words()
     return [w for w in word_list if not w in stop_words]
 
 def frequencies(word_list):
-    """
-    Takes a list of words and returns a dictionary associating
-    words with frequencies of occurrence
-    """
-    print "My name is " + inspect.stack()[0][3] + " and my arguments are " + str(locals().keys())
+    # Meta-level data: inspect.stack() and locals()
+    print "My name is " + inspect.stack()[0][3] + ", my arguments are " + str(locals().keys())
+    print "   and I'm being called from ", inspect.stack()[1][3]
     word_freqs = {}
     for w in locals()['word_list']:
         if w in word_freqs:
@@ -36,19 +37,19 @@ def frequencies(word_list):
     return word_freqs
 
 def sort(word_freq):
-    """
-    Takes a dictionary of words and their frequencies
-    and returns a list of pairs where the entries are
-    sorted by frequency 
-    """
+    # Meta-level data: inspect.stack() and locals()
     print "My name is " + inspect.stack()[0][3] + " and my arguments are " + str(locals().keys())
+    print "   and I'm being called from ", inspect.stack()[1][3]
     return sorted(locals()['word_freq'].iteritems(), key=operator.itemgetter(1), reverse=True)
 
 #
 # The main function
 #
-word_freqs = sort(frequencies(extract_words(sys.argv[1])))
+def main():
+    word_freqs = sort(frequencies(extract_words(sys.argv[1])))
+    for (w, c) in word_freqs[0:25]:
+        print w, ' - ', c
 
-for tf in word_freqs[0:25]:
-    print tf[0], ' - ', tf[1]
+if __name__ == "__main__":
+    main()